Npgsql parameters

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. This query executed correctly and issued the necessary data, but as soon as I add parameter to the sql in the section "select". This raises the question: is there a way to dynamically insert a list of fields using suchlike parameters?

Unfortunately, Npgsql doesn't have support for what you are trying to do. NpgsqlParameter values are supposed to be only used as parameter values in the where clause. In order to add field names dynamically as you intend, you will have to create the query manually by using string concatenation. Learn more. Asked 5 years, 9 months ago. Active 2 years, 10 months ago. Viewed 4k times. AddWithValue "param2", 1 ; This query executed correctly and issued the necessary data, but as soon as I add parameter to the sql in the section "select" SqlCommand.

AddWithValue "param1", ",field1" ; SqlCommand. AddWithValue "param2", 1 ; it gives me some kind of nonsense. That's not how parameterized queries work at all, in any database that supports them instead of faking them.

They represent valuesnot string substitutions. Active Oldest Votes. I hope it helps.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. Npgsql can not determine parameter types for NpgsqlCommand.

Problem tested with PostgreSQL 9. NET 4. This problem was introduced with commit de3e on Aug 09, Hi, Glen! Can you have a look at this issue? I can confirm this problem in my tests. Thanks in advance. Not sure why we need to make up error messages that bear no resemblance to the real one This is what I get:.

Hmmmm, I was playing with and made a drastic change in NpgsqlParameter to return false for the UseCast property. When I run our testsuite, I could see a lot of tests failing with a message about not being able to determine the parameter type. This problem can be gotten around nicely by setting the type explicitly on the parameter to NpgsqlDbType.

Npgsql's parameter system has some serious issues. I was working on a rewrite some months ago there's a PR work in progressand I was never able to quite get it right; I couldn't get all the tests to pass. I never absorbed the type system sufficiently to understand it completely. But there's no way I can devote enough time to it now to finish it, and I see no simple path at all to get it all working properly.

Thanks for having a look at this, Glen! I agree with you about the Npgsql type system. It is really very ugly. I'll have a look at this. Ok, I found the culprit: when the parameter value is set, the useCast property isn't set to be used. It keeps its default value of false. I didn't check the code yet, but I think it expects to receive from the server the type of the pareameter when doing the bind.

Prepared Statements

As the type isn't received, Npgsql seems to be sending null 0x That's why setting the DbType, as suggested by glenebobalso made it work. It sets the useCast property to true too.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub? Sign in to your account. When NpgSqlCommand is created with a string that contains escaped apostrophe, the parameters in the query after this string are not substitued even though the valid values are provided. Such parameters placed before the string with apostrophe are substitued correctly.

If the someValue would be placed before the 'b''la' string, everything would work. I think it could be problem in NpgsqlCommand. AppendCommandReplacingParameterValues method. Check out PR. PR merged.

Please have a look. This is fixed in Npgsql 2. Please, give it a try and let us know if you find any other problem. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together. Sign up. New issue. Jump to bottom. Labels bug. Milestone 2. Copy link Quote reply. This comment has been minimized.

Sign in to view. Fix bugs andparameter substituion troubles Fix bugs andparameter substituion troubles. Simplfied repro unit test bugs and …. This is about as simple as I can make it.

Fix for bugs and …. Properly handle escaped single quote character '' in a quoted section during query parameter substitution. Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment.GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. Already on GitHub?

npgsql parameters

Sign in to your account. I have recently updated npgsql to the current version 3. I noticed the same regression. Does it help for you if you set the parameter names to empty strings ""? Sorry for not commenting earlier, this issue slipped through the cracks. I'll try to take a look for 3. This is caused bywhich adds named parameters function calls.

Basically the problem is that your parameters have named :Id:Code but your function is defined without parameter names. When your Npgsql parameters have names, Npgsql makes the function call by name, which will fail if your PostgreSQL function doesn't have the corresponding name.

You can either add parameter names to your PostgreSQL function, or remove the names from the Npgsql parameters. Skip to content. Dismiss Join GitHub today GitHub is home to over 40 million developers working together to host and review code, manage projects, and build software together.

Sign up. New issue. Jump to bottom.

Supported Types and their Mappings

Copy link Quote reply. StoredProcedure; sqCommand. AddWithValue ":Id", company. Id ; sqCommand. AddWithValue ":Code", company. Trim ; sqCommand. AddWithValue ":Name", company. AddWithValue ":SocialName", company. AddWithValue ":Web", company.

AddWithValue ":ImagePath", company. AddWithValue ":Active", company. Active ; sqCommand. This comment has been minimized. Sign in to view. Am closing this, although feel free to comment further. Sign up for free to join this conversation on GitHub.

Already have an account? Sign in to comment.Note that in addition to the below, enum and composite mappings are documented in a separate page. Note also that several plugins exist to add support for more mappings e. The Default. GetValue will return. GetProviderSpecificValue will return a value of a data type specified in the Provider-specific type column, or the Default. NET type if there is no specialization.

These can be retrieved by calling NpgsqlDataReader. Range or NpgsqlDbType. Array with the child type. Range NpgsqlDbType. Array NpgsqlDbType.

VIDEO -STEPS to setup Npgsql (.Net Data Provider for Postgres)

For information about enums, see the Enums and Composites page. Read mappings The following shows the mappings used when reading values.

Npgsql Basic Usage

The default type is returned when using NpgsqlCommand. ExecuteScalarNpgsqlDataReader. GetValue and similar methods. You can read as other types by calling NpgsqlDataReader.

Provider-specific types are returne by NpgsqlDataReader. PostgreSQL type Default. NET type Provider-specific type Other. If the parameter's DataType is set, it is used.

npgsql parameters

If the parameter's DbType is set, it is used. If none of the above is set, the backend type will be inferred from the CLR value type. Improve this Doc.Initializes a new instance of the NpgsqlParameter class.

Initializes a new instance of the NpgsqlParameter class with the parameter name and the data type. Initializes a new instance of the NpgsqlParameter. The total number of digits to the left and right of the decimal point to which Value is resolved. The total number of decimal places to which Value is resolved. An System. Object that is the value of the NpgsqlParameter.

Initializes a new instance of the NpgsqlParameter class with the parameter name and a value of the new NpgsqlParameter. When you specify an System. Object in the value parameter, the System. DbType is inferred from the. NET Framework type of the Object. When using this constructor, you must be aware of a possible misuse of the constructor which takes a DbType parameter.

This happens when calling this constructor passing an int 0 and the compiler thinks you are passing a value of DbType. Use Convert. ToInt32 value for example to have compiler calling the correct constructor.

Connection String Parameters

Can be used to communicate a value from the validation phase to the writing phase. To be used by type handlers only. One of the System. DbType values. The default is Object. Gets or sets the NpgsqlDbType of the parameter. One of the NpgsqlDbType values. The default is Unknown. Object that is the value of the parameter. The default value is null. Gets or sets The name of the NpgsqlParameter. The name of the NpgsqlParameter. The default is an empty string. This property is automatically set if parameters have been derived via DeriveParameters NpgsqlCommand and can be used to acquire additional information about the parameters' data type.

Gets or sets the maximum number of digits used to represent the Value property. The maximum number of digits used to represent the Value property. The default value is 0, which indicates that the data provider sets the precision for Value.

Gets or sets the number of decimal places to which Value is resolved. The number of decimal places to which Value is resolved.

The default is 0. Creates a new NpgsqlParameter that is a copy of the current instance. A new NpgsqlParameter that is a copy of this instance. Class NpgsqlParameter This class represents a parameter to a command that will be sent to server. Inheritance System.When sending data values to the database, you should use parameters rather than including the values in the SQL as follows:. The p in your SQL is called a parameter placeholder ; Npgsql will expect to find a parameter with that name in the command's parameter list, and will send it along with your query.

This has the following advantages over embedding the value in your SQL:. Note that PostgreSQL does not support parameters in arbitrary locations - you can only parameterize data values. For example, trying to parameterize a table or column name will fail - parameters aren't a simple way to stick an arbitrary string in your SQL.

PostgreSQL has a strongly-typed type system; columns and parameters have a type, and types are usually not implicitly converted to other types. This means you have to think about which type you will be sending: trying to insert a string into an integer column or vice versa will fail. NET type: when Npgsql sees a. NET stringit automatically sends a parameter of type text note that this isn't the same as, say varchar. In many cases this will work just fine, and you don't need to worry.

In some cases, however, you will need to explicitly set the parameter type. For example, Npgsql sends. For more information on supported types and their mappings, see this page. NpgsqlParameter exposes several properties that allow you to specify the parameter's data type:.

DbType is a portable enum that can be used to specify database types. While this approach will allow you to write portable code across databases, it obviously won't let you specify types that are specific to PostgreSQL. This is rarely needed - NpgsqlDbType should be suitable for the majority of cases. However, it may be useful if you're using unmapped user-defined types enums or composites or some PostgreSQL type which isn't included in NpgsqlDbType because it's supported via an external plugin.

The standard ADO. Valuewhich, being an objectwill box value types such as int. If you're sending lots of value types to the database, this will create large amounts of useless heap allocations and strain the garbage collector. This generic class has a TypedValue member, which is similar to NpgsqlParameter.

npgsql parameters

Value but is strongly-typed, thus avoiding the boxing and heap allocation. Note that this strongly-typed parameter API is entirely Npgsql-specific, and will make your code non-portable to other database. See for an issue discussing this at the ADO. NET level. Once a function or procedure has been defined, calling it is a simple matter of executing a regular command:. You can replace the parameter values above with regular placeholders e.

In some other databases, calling a stored procedures involves setting the command's behavior :. Npgsql supports this mainly for portability, but this style of calling has no advantage over the regular command shown above. When CommandType. Unless you have specific portability requirements, it is recommended you simply avoid CommandType.

StoredProcedure and construct the SQL yourself. Note that if CommandType. This means that your NpgsqlParameter names must match your PostgreSQL function parameters, or the function call will fail. If you omit the names on your NpgsqlParameters, positional notation will be used instead. See the PostgreSQL docs for more info.

Be aware that CommandType.


Comments

Add a Comment

Your email address will not be published. Required fields are marked *